Wheat is grown worldwide and is the most widely adapted cereal. There are five main wheat market classes. They include the four common wheat (Triticum aestivum L.) classes: hard red winter, hard red spring, soft red winter, and white. The fifth class is durum (Triticum turgidum L.). Common wheats are used in a variety of food products such as bread, cookies, cakes, crackers, and noodles. In general the hard wheat classes are milled into flour used for breads and the soft wheat classes are milled into flour used for pastries and crackers. Wheat starch is used in the food and paper industries, as laundry starches, and in other products. Because of its use in baking, the grain quality of wheat is very important. To test the grain quality of wheat for use as flour, milling properties are analyzed. Important milling properties are relative hardness or softness, weight per bushel of wheat (test weight), siftability of the flour, break flour yield, middlings flour yield, total flour yield, flour ash content, and wheat-to-flour protein conversion. Good processing quality for flour is also important. Good quality characteristics for flour from soft wheats include low to medium-low protein content, a low water absorption, production of large-diameter test cookies and large volume cakes. Wheat glutenins and gliadins, which together confer the properties of elasticity and extensibility, play an important role in the grain quality. Changes in quality and quantity of these proteins change the end product for which the wheat can be used.